Liquid heater



'O-ct. 16, s1945. H. w. HAYWARD LIQUID HEATER Filed Nav.. 9, 1943 5sheets-snet 1 V.. AE.,

ILNFVENTOR. j W/ Oct. 16, 1945.

'H. w. HAYWARD LIQUID HEATER Filed Nov. 9, 1943 Wwmmm I 3 Sheets-Sheet 2@my l @Ww/Wy oct; 16, 1945.

H. W. HAYWARD LIQUID HEATER Filed Nov. 9, 1943 3 Sheets-Sheet 3 EV'AMINVENTOR.

@my BY Patented Oct. 16, 1945 UNITEDY STATES PATENT OFFICE LIQUID HEATERf Henry W. Hayward, Irondequoit, N. Y.

Application November 9, 1943, Serial No. 509,582 16 claims. (01.219-39)This invention relates to liquid heaters, such, for example, as waterheaters for residential installations, one object of the invention beingto provide an improved and more practical and economical heater of thecharacter described, adapted tov be heated by either gas burner means orelectrical resistance elements, as desired.

Another object is to provide such a heater capable of furnishing anample supply of hot water, or other liquid, with quick recovery oftemperature after service demands thereon, while at the same timerequiring heat input at a more constant rate.

' A further object is to afford a heater of the character describedcapable ofy maintaining in storage at al1 times a substantial quantityof hot Water suiicient for normal immediate needs, produced by asuccession of heating periods so as to spread out over a relatively longtime the total required heat input, thus combining the advantages of aninstantaneous type heater with those of a slow recovery heater butWithout the known disadvantages of such prior heaters.

Still a further object is to provide such a, heater having, incombination with the above features, an advantageous arrangement forreducing radiation losses and so additionally increasing the operatingefiiciency.

To these and other ends the invention resides in certain improvementsand combinations of parts, all as will be hereinafter more fullydescribed, the novel features being pointed out in the claims at the endof the speciiication.

In the drawings:

Fig. l is a central, vertical section of a heater of the electrical typeembodying the present in- Vention;

Fig. 2 is a horizontal section on the line 2a-2a in Fig. l;

Fig. 3 is an enlarged, sectional view illustrating the Mercoid typeswitch employed in the present embodiment;

Fig. 4 is a diagram of the electrical circuit employed in a heater ofthe type shown in Fig. l;

Fig. 5 is a View similar to Fig. 1 oi a modiiied embodiment of theinvention, comprising gas burner heating means; y

Fig. 6 is a horizontal section on the line 15a-Ea in Fig. 5;

Fig. '7 is a vertical, sectional View on the line 'lo-'la in Fig. 5;

Fig. 8 is an enlarged, vertical view of the gas burner means shown inFig. 5, and

Fig. 9 is a diagram of the electrical circuit for controlling theheating means shown in Fig. 5.

Cil

The preferred Yembodiment of the invention, herein disclosed by Way ofillustration, comprises a combination of liquid heating and storingchambers one of Which,'herein termed the "primary storage container isemployed to heat and hold a Substantial body of hot Water ready forimmediate use, While the other termed the secondary storage containerencompasses the primary container and serves as a preheating chamber, asWell as a means of insulating the primary container against heat losses,the heat being preferably supplied directly to and also interchangedbetween the containers in such a way as to insure rapid recovery afterservice demands and operating at a substantially constant rate of heatinput.

Referring more particularly to the drawings, the primary rstoragecontainer is shown at 20 (Figi) in the fonm of a vertically arranged,cylindrical, metal drum having at its top an outlet pipe 2l forsupplying the heated water for use.A The secondary storage container isshown at 23 inthe form of an annular casing, the outer cylindrical wallsof which are of substantially greater diameter than container v20, whilethe inner walls of container 23 are formed by the Walls of container 20with which container 23 is connected in a fluid-tight manner by means oftop flange 24 and the bottom 25 of container 23. The secondary containerthus encloses an annular space, 26, of substantial capacity but is ofsubstantially less height than container 2l), the upper' portion 21 ofwhich extends above the top of container 23, preferably as an extensionof its cylindrical lower portion, although such upper portion 21 mayhave any other suitable shape. Container 23 has communicating therewitha water inlet pipe 28, as shown.

As indicated above, the water, or other liquid to be heated, isintroduced to the unit through 'pipe 28 connected with the secondary orouter container 23, and is discharged from the top of the primary orinner container 21 through the pipe 2l, and means are provided for thenow of the Water from container 23 to container 20 to replace thatwithdrawn by service demands. Such means comprises, preferably, asuitable number of openings 29 in the lower portion of the common Wall3H between the containers, these openings being shrouded by conductingbaiiies or hoods 3|, open at their tops 32 which are positioned forcommunication with the upper portion of the secondary container 23. Bythis means the preheated water collecting in the upper portion ofsecondary container 23 may flow downwardly through the hoods 3| andopenings 29 into the lower portion of the primary container 20, theopenings 29 being located at approximately the level at which the Watertemperature corresponds with that of the preheated water supplied fromcontainer 23,

Means are provided for directly heating the water in the lower portionof the primary container, 2B, from which the heat is transmitted throughthe common wall 3U to'preheat the water in the secondary container 23.While such a heating arrangement may be sufficient for someinstallations, it is preferred to provide means also for supplying heatdirectly to the water in the secondary container 23, and such a heatingsystem, of the electrical resistance type, will now be` described.

The electrical heating means preferably comprises an electricalresistance heating element in the form of a horizontal loop 33 (Figs. 1,2 and 4), supported by an outlet box 34 positioned in a recess 35 in thesecondary container and having a liquid-tight t in an opening in primarycontainer 20, with the heating element projecting into the primarycontainer, as shown in Fig.' 2. A similar heating element is providedfor the secondary container in the form of a vertically arranged andcurved loop 35, carried by an outlet box 31 having a liquid-tight fit inan opening in the outer wall ofthe container, as shown, heating elements33 and 36 being both connected with temperature responsive elementslocated in the containers. l

Such temperature responsive elements preferably comprise a switch 38 ofthe Mercoid" type, f

illustrated in Fig. 3, which is connected to and oscillated bytemperature responsive means of any known or suitable variety, as wellunderstood in the art,'such devices being enclosed' in liquidtighthousings projecting in liquid-tight arrangement through-openings inthecontainer walls. Each switch comprises a pair of electrical terminals 39and 40, extending in pairs in sealed rela-V tion through the ends 'oftheglass tube 4l,'in which is a body of mercury 42 for electricallyconnecting the terminals of each pair as the tube 4| istipped to drivethe mercury to one end or the other. One such temperature responsivede-` vice is located at 43 in the upper portion 21 of the primarycontainer in which the hot water is stored for use. Another 'such device44 is located in container 21 a short distance above device 43, while athird temperature responsive vdevice 4-5 is located in the upper portionof secondary container 23.

These temperature responsive devices are connected in circuit with theheating elements 33 and 36, as shown in Fig. 4,`fron'1 which it will beseen' thattemperature responsive device 43 operates to connect one side46 of-'thepower'line alternately with one or the other of the heatingelements, being shown in position in Fig. 4 for energizingthe heatingelement 33 ofthe primary container. The circuit including the heatingelement 35 of the second-ary container includes the ai.

close the circuit including the heating means in the secondarycontainer. When the temperature of the water reaches a predeterminedhigh limit in the top of the secondary container, its temperatureresponsive element 45 and associated switch will then deenergize itsheating element When a demand on the unit reduces the temperature at thetemperature responsive element 43, so as to result in closing of itsassociated switch and the energizing of its heating element 33, then thecircuit through the heating means of the secondary container will beopen,

1 the separate heating means for the respective temperature responsivedevice 45 located in the tion of the primary container is heated down toYthe level of the temperature responsive element 43, the associatedswitch will be operated to disconnect the'primary heating 6161116111133@nd containers being thus operated in an alternating fashion which, withthe continuous transfer of heat through the common wall between thecontainers, tends to produce a more uniform rate of heat input.

When the temperature at the responsive device 44 in the upper portion ofthe primary container reaches a predetermined high limit, it operatesthe associated switch to deenergize the heating means in bothcontainersuntil the temperature drops again within the desired operating range. Itwill be seen that the secondary container is not only heated in partfrom the primary container through their common wall surfaces, butserves, in addition, to insulate the lower portion of the primarycontainer, and conserve the heat which would otherwise be radiated fromit and otherwise dissipated and lost, Such encompassing location of thesecondary container, on the outside of the primary container, presentswater of lower temperature at the outer surfaces ofsuch portions of theunit to further reduce the dissipation of heat, and these features aiorda greatly increased operating eiciency. The compact association anddesign of the two containers, furthermore, is such as to facilitate theencasement thereof in a substantial jacket of efficient insulatingmaterial of any known or suitable variety indicated at48, as wellunderstood in the art.

Starting with the inner or heating chamber full of water at, say 160 thethermostat 43 will deenergize thel heat' source. Heat transfer willimmediately occur through the common wall between the containers intothe water in the secondary or outer containerY so as to preheat it. Thisin time will cool the water in the primary cr inner container to adegree below the setting of its thermostat, thus reenergizing its heatsource until its water is again raised to the setting of its thermostatand its heat again shut ofi. The hottest water will collect, of course,in the upper portion of the primary container, from which it iswithdrawn, as required, through pipe 2l. On such withdrawal, makeupwater which has been preheated and collected inthe top of the secondarycontainer, will be admitted to the primary container through the hoods3l and openings 29. .This will result in lowering the temperature of thewater in the primary container and the reenergizing of its heatingmeans, followed by reenergizing of the heating means in the secondarycontainer, to supplement theV heat 'supplied by tansmission through thecommon wall. It will be noted, however, thatthe water'admitted to theprimary container willlbe preheated to a temperature of, say, 100 F., ascontrolled by the setting of thermostat 45Y in the secondary container,so as to require further heating in the primary container through arange of only 60 F., thereby decreasing the heat input required in theprimary demand on its storage supply.

Thus the heating operation and maintenance of temperature in the primarycontainer will proceed in a series of steps of alternate operation ofits heat source and loss of temperature to the secondary container, withthe result that the temperature of the Water in the primary contanerwill be maintained nearly constant, while intermittently transferringheat to the encompassing secondary container for additional storage inthe form of preheated water. The secondary container may or may not bedirectly supplied with heat depending, for example, upon the applicationto it of the separate heating means described, or, when applied, uponthe setting of its temperature responsive element. Such direct heatingof the secondary container may be preferable, for example, ininstallations operated at a relatively high rate of duty.

ln Figs. 5 to 9, inclusive, there is shown a modified constructioncomprising gas burner heating means for one or both containers. Thisembodiment employs a similar primary container 49, with an outletconnection 5D, and an encompassing secondary container 5l, which has thesame construction and arrangement as described above, except for asomewhat larger diameter. Similar openings 52 are provided in the commonwall between the containers, shrouded by conducting hoods 53,communicating with the upper portion of the secondary container, whichis provided with an inlet connection 54.

In this modified embodiment, however, the electrical resistance heatingelements are replaced by fuel gas burners 55 and 56, each of a sizesuitable for its associated container. The products of combustion fromburner 55 pass into a iiue 57, which rises through the water in theprimary container 49, to heat the same and out through a stack 5S. Theproducts of combustion from burner 56 pass into a nue 59, which risesthrough the water in the secondary container and to the stack 58.

The fuel gas is supplied to burner 55 from a main connection 6Bcontrolled by a valve 5l operated by a horizontal solenoid 62 and spring53, as well understood in the art. A branch pipe 64, leading directly toburner 55, is similarly controlled by a. valve 65 operated by avertically arranged solenoid G6, as well understood in the art.

Burner 55 is supplied through a branch line 51, 'y'

similarly controlled by a valve 68, operated by a similar solenoid E9.At 'm is a pilot means for lighting each burner supplied through a pipe1|.

The temperature responsive elements 12, 'i3 and 14, associatedrespectively with Mercoid switches 75, 15 and l?, are of the sameconstruction and arrangement as explained in connection with theembodiment first described, and are employed to control the solenoids65, 5S and 52. Element T2, with its switch 15, contro-ls solenoid 66 andthe circuit of solenoid 69, for alternate operatic-n of the valves 65and 68, Element 14. with its switch 11, directly controls solenoid 59and valve 68, while element '13, with its switch T6, controls solenoid62 and main valve 5I. operation of this control system is the same asthat of the electrical system of the embodiment nrst described, withcorresponding operatic-n of the containers and the unit as a whole.

It will be apparent from the description of the foregoing embodiments ofthe invention that they provide a unit having a heat storage chamberelevated above and protected from the cooling effect of the secondarychamber, so as to afford an ample reservoir of heated water held readyThe "l for instant use. The concentric and encompassing preheatingcontainer, with its common wall surfaces, absorbs a large proportion ofthe heat dissipated from the primary container to provide preheating ofthe water supply, assisted by direct heating means, if desired, thuscontributing to a rapid recovery rate and efiicient operation. A furtheradvantage resides in a more constant rate of heat and power input, whichfacilitates eicient service on the part of the electrical or gas powerutility by which the unit is supplied.

It will thus be seen that the invention accomplishes its objects andwhile it has been described in preferred forni and in detail, it is tobe understood that such description is intended in an illustrative.rather than a limiting sense, as it is contemplated that various changesin the construction and arrangement of the parts will readily occur tothose skilled in the art Within the spirit of the invention and thescope of the ap pended claims.

I claim:

1. A liquid heater comprising a. primary storage container havingcommunicating upper and lower portions, said upper portion being adaptedand arranged to store a supply of heated liquid ready for use and havinga liquid outlet, a secondary storage container having a liquid inlet,means for heating the liquid in said primary container, said lowerportion only of said primary container and said secondary containerhaving common wall surfaces therebetween of substantial extent fortransferring heat from the liquid in said lower portion only of saidprimary container to the liquid in said secondary container to preheatthe same, and a connection from the upper portion of said secondarycontainer to said lower portion of said primary container fortransmitting thereto the liquid preheated in said secondary container.

2. A liquid heater comprising a primary storage container having athermally insulated upper portion provided with a liquid outlet, asecondary storage container having a liquid inlet, means for heating theliquid in said primary container, said containers having wall surfacescommon to substantially the full height of said secondary container butto the lower portion only of said primary container, for transferringheat from the liquid in the lower portion only of said primary containerto the liquid in said secondary containe;` to preheat the same, withoutsubstantially affecting the temperature of the supply of heated liquidcontained in the upper portion of said primary container, and aconnection from the said secondary container to said lower portion ofsaid primary container for transmitting thereto the liquid preheated insaid secondary container.

3. A liquidv heater comprising a primary storage container having aliquid outlet, a secondary storage container having a liquid inlet,means for heating the liquid in said primary container, said primarycontainer having an upper po-rtion extending above said secondarycontainer for storing heated liquid ready for use and said containershaving common wall surfaces arranged therebetween for transferring heatfrom the liquid iny the lower portion only of said primary container tothe liquid in said secondary container to preheat the same, withoutsubstantially affecting the temperature of said heated liquid in saidupper portion, and a connection from said secondary container to saidlower portion of said primary container for transmitting thereto theliquid preheated in said secondary container.

4.'.A liquid heater comprising a primary storage container having aliquid outlet, a secondary storage container having a liquid inlet,means for Vheating the liquid in said primary container, said primarycontainer having an upper portion extending above said secondarycontainer and provided with said outlet for storing and supplying heatedliquid ready for use and said containers yhaving common wall surfacespositioned therebetween below said upper portion of said primarycontainer for transferring heat from' the liquid in the lower portion ofsaid primary container to the liquid in said secondary container topreheat the same, and a connection leading downwardly from the liquid inthe upper portion of said secondary container to a region of liquidhaving substantially the same temperature in the lower portion of saidprimary container for transmitting thereto the liquid preheated in saidsecondary container.

5. A liquid heater comprising a primary 'storage container havingcommunicating upper and lower portions, said upper portion being-vprovided' with a liquid outlet, a secondary storage container ofsubstantially annular shape encircling said lower portion only of saidprimary container and having a liquid inlet, means for heating theliquid in said primary container, said Vlower portion only of saidprimary container and said secondary container having common wallsurfaces therebetween of substantial extent for transferring heat fromthe liquid in said lower portion of said primary container to the liquidin said secondary container to preheat the same, without substantiallyaffecting the temperature of said heated liquid -in said upper portion,and a connection from the upper portion of said secondary container tosaid lower portion of said primary container for transmitting theretothe Y liquid preheated in said secondary container.

6.- A liquid heater comprising a primaryfstor- 'age container having aliquid outlet,` a secondary storage container of substantially annularshape encircling the lower portion only of said primary container andhaving a liquid inlet means immersed in and surrounded by the liquid ofsaid primary container for heating the same,r the wall of said primarycontainer and the inner wall of said secondary container comprisingcommon metal wall surfaces therebetween for transmitting heat from theliquid in said lower portion only of said primary container to theliquid in said secondary container to preheat the same, withoutsubstantially affecting the temperature of the supply of heated liquidcontained in the upper portion of said primary container, and aconnection from the upper portion of said secondary container to saidlower portion of said primary container intermediate the top and bottomthereof for transmitting thereto the liquid preheated in said secondarycontainer.

'7.' A liquid heater comprising a primary storage container havingcommunicating upper and lower portions, said upper portion having aliquid outlet, a secondary storage container having a liquid inlet,separate means for heating said containers, respectively, temperatureresponsive means in said containers for controlling each of said heatingmeans, said lower portion of said primary container and said secondarycontainer having common metal wall surfaces therebetween of substantialextent for transferring heat from the liquid in said lower portion ofsaid pri- Cil -mary container toxthe liquid in said secondary containerto' additionally preheat the same, without substantially aiecting thetemperature of the supply of heated liquid contained in the upperportion of said primary container, and a connection from said upperportion of said secondary containerto said lower portion of saidprimarycontainer for transmitting thereto the liquid preheated in saidsecondary container.

8. A liquid heater comprising a primary-storage container having aliquid outlet, a secondary storage container of substantially annularshape encircling the lower portion only of said primary container andhaving al liquid inlet, separate means for heating said containers,respectively, temperature responsive means in said containers forcontrolling each of said heating means,v the wall of said lower portionof said 4primary container and the inner wall of said secondarycontainer providing common wall surfaces therebetween for transferringheat from the liquid in said lower portion of said primary container tothe liquid in said secondary. container to additionally preheat thesame, without substantially aifecting the temperature of the supply ofheated liquid contained inthe upper portion ofv said primary container,and a connection from the upper portionv of said secondary container tosaid lower portion of said primary container for transmitting theretothe liquid preheated in said secondary container.

9. A liquid heater comprising a primary storage container havingcommunicating upper vand lower portions, said upper portion-beingadapted and arranged tostore a supply of heated liquid ready for use andprovided with a liquid outlet, a secondary storage container having aliquid inlet, means including a separate gas burner for each of saidcontainers having a iiue extending through the liquid therein forheating the same,

,means in said containers for controlling said gas burners, said lowerportion only of said primary container and said secondary containerhaving common wall surfaces therebetween for transferring heat from theliquid in said lower portion only of said primary container to theliquid in said secondary container to additionally preheat the same, anda connection from the upper portionrof said secondary container to saidlower portion of said primary container` for transmitting thereto theliquid preheated in said secondary container.

10. A liquid heater-comprisingra primary storage container-having aliquid outlet, a secondary storage container having a liquid inlet,means including a separate gas burner for each of said containers havinga flue extending throughV the liquid therein for heating the same, meansin said containers for controlling said gas burners, said primarycontainer having an upper portion extending above said secondarycontainer for storing heated liquid ready for use and the lower portionof said primary container and saidv secondary container having commonwall surfaces therebetween for transferring heat from the liquid in thelower portion of said primary container to the liquid` in said secondarycontainer to additionally preheat the same, and a connection from theupper portion-of said secondary container to said lower portion of saidprimary container for transmitting thereto the liquid preheated in saidsecondary container. Y t t l1. A liquid heater comprising a primarystorage container having communicating upper and lower portions, saidupper portion being adapted and arranged to store a supply of heatedliquid ready for use and having a, liquid outlet, a secondary storagecontainer having a liquid inlet, means including a separate gas burnerfor each of said containers having a flue extending through the liquidtherein for heating the same, temperature responsive means in saidprimary container arranged to effect the energizing of said heatingmeans in alternation with each other, said lower portion of said primarycontainer and said secondary container having common wall surfacestherebetween for transferring heat from the liquid in sai-d lowerportion of said primary container to the liquid in said secondarycontainer to additionally preheat the same, and a connection from theupper portion of said secondary container to said lower portion of saidprimary container for transmitting thereto the liquid preheated in saidsecondary container.

l2. A liquid heater comprising a primary storage container having aliquid outlet, a secondary storage container having a liquid inlet,means including an electrical heating element immersed in and surroundedby the liquid in each of said containers, for heating the same,temperature responsive means in said containers for controlling saidelements, said primary container having an upper portion extending abovesaid secon-dary container for storing heated liquid ready for use andthe lower portion of said primary container and said secondary containerhaving common wall surfaces therebetween for transferring heat from theliquid in the lower portion of said primary container to the liquid insaid secondary container to additionally preheat the same, and aconnection from said secondary container to said lower portion olf saidprimary container for transmitting thereto the liquid preheated in saidsecondary container.

13. A liquid heater comprising a primary storage container having` aliquid outlet, a secondary storage container having a liquid inlet,separate means for heating the liquid in said containers, respectively,temperature responsive means in said primary container arranged to eiectthe energizing of said heating means in alternation with each other,said containers having common wall surfaces therebetween of substantialextent for transferring heat from the liquid in said primary containerto the liquid in said secondary container to additionally preheat thesame, and a connection from said secondary container to said primarycontainer for transmitting thereto the liquid preheated in saidsecondary container.

14. A liquid heater comprising a primary storr age container havingcommunicating upper and lower portions, said upper portion being adaptedand arranged to store a supply of heated liquid and having a liquidoutlet, a secondary storage container having a liquid inlet, separatemeans for heating the liquid in said containers, respectively,temperature responsive means in said primary container arranged to electthe energizing of said heating means in alternation with each other,said lower portion only of said primary container and said secondarycontainer having common wall surfaces therebetween for transferring heatfrom the liquid in said lower portion only of said primary container tothe liquid in said secondary container to additionally preheat the same,and a connection from said secondary container to said lower portion ofsaid primary container for transmitting thereto the liquid preheated insaid secondary container.

15. A liquid heater comprising a primary storage container having aliquid outlet, a secondary storage container having a liquid inlet,separate means for heating the liquid in said containers, respectively,temperature responsive means in said primary container arranged toeffect the energizing of said heating means in alternation with eachother, temperature responsive means in each of said containers fordeenergizing the heating means thereof at a predetermined maximumtemperature, respectively, said containers having common wall surfacestherebetween of substantial extent for transferring heat from the liquidin said primary container to the liquid in said secondary container toadditionally preheat the same, and a connection from said secondarycontainer to said primary container for transmitting thereto the liquidpreheated in said secondary container.

16. A liquid heater comprising a primary storage container havingcommunicating upper and lower portions, said upper portion being adaptedand arranged to store a supply of heated liquid and having a liquidoutlet, a secondary storage container having a liquid inlet, separatemeans for heating the liquid in said containers, respectively,temperature responsive means in said primary container arranged toeffect the energizing of said heating means in alternation with eachother, temperature responsive means in each of said containers fordeenergizing the heating means thereof at a predetermined maximumtemperature, respectively, said lower portion only of said primarycontainer and said secondary container having common wall surfacestherebetween for transferring heat from the liquid in said lower portiononly of said primary container to the liquid in said secondary containerto additionally preheat the same, without substantially affecting thetemperature of said heated liquid in said upper portion of said primarycontainer, and a connection from the upper portion of said secondarycontainer to said lower portion of said primary container fortransmitting thereto the liquid preheated in said secondary container.

HENRY W. I-LAYWARD.

